Staple driving machine



sept 13, 1949. M. E. WAMPLER 2,481,892

STAPLE DRIVING MACHINE Filed Sept. 28, 1946 2 Sheets-Sheet l i fm @heb/H12 Wumpler (T'ronNaY-J v M. E.wAMP| ER 2,481,892

sept. 13, 1949.

Filed sept. 28, 1946 2 Sheets-Sheet 2 C/TYlelviIle C-Mfol fswh m pl e r wx. ',flrTonNBY-J Patented Sept. 13, 1949 UNITED STATES PATENT OFFICE STAPLE DRIVING MACHINE Melville Earl Wampler, Chicago, Ill., assigner, by mesne assignments, to Acme Staple Company, Camden, N. J., a corporation of New Jersey Application September 28, 1946, Serial No. 700,099

11 Claims.

The invention relates to staple driving machines generally and more particularly to machines of the spring-driven hammer or tacker type.

One object of the invention is to provide improved hammer driving mechanism for machines of the above general character which is simple in construction and powerful and efficient in operation, and which has few parts subject to wear, all of which parts are readily accessible for replacement.

Another object is to provide a staple driving machine which is compact and light in weight, and which ts conveniently in the hand, thus permitting use for long periods without unduly tiring the operator.

A further object is to provide a staple driving machine adapted to be constructed largely of parts formed by simple stamping or die forming operations, thus substantially reducing manufacturing costs.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawings, in which:

Figure 1 is a longitudinal sectional view of a staple driving machine embodying the features of the invention.

Fig. 2 is a side elevational View of the machine with a part of the casing broken away to show the hammer driving mechanism in retracted or cocked position.

Fig. 3 is a fragmentary side view showing the actuating pawl of the driving mechanism substantially at the instant of release.

Fig. 4 is a transverse sectional view taken in a vertical plane substantially on the line 4-4 of Fig. 2.

Fig. 5 is a sectional view taken in a horizontal plane substantially on the line 5-5 of Fig. 1.

Fig. 6 is an exploded view of the casing showing the form and relationship oi the component parts.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but

it is to be understood that I do not thereby intend to limit the invention to the specic form disclosed, but intend to cover all modications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

For purposes of illustration the improved staple driving machine has been shown in the form of a tacker adapted to drive staples through tags or 6 the like to attach them to boxes or other structures. It will be apparent that the novel features of construction may also be used in stapling machines of the type adapted to drive staples through two or more sheets of material and clinch them on the underside thereof to secure the sheets together.

The machine selected to illustrate the invention comprises generally a hollow rectangular casing I0 having a centrally disposed elongated opening I I extending through it from side to side to provide for gripping the machine in one hand. The opening ll is positioned so as to divide the interior of the casing into front and rear compartments I2 and I3 connected by horizontally disposed upper and lower compartments I4 and I5. Extending longitudinally of the casing within the lower compartment I5 is a guideway I6 along which staples I'I, herein shown as U-shaped in form, are fed successively to a reciprocating hammer I8 supported and guided in the front compartment I2 of the casing. The hammer is adapted to be retracted manually and to be advanced in its staple driving stroke by spring-actuated mechanism I9 under control of a hand lever 20. The hand lever is pivotally supported on the front end of the casing and disposed so that it may be grasped by the hand gripping the casing.

In accordance with the invention the hammer actuating mechanism I9 is constructed so as to provide ample power for driving the staples Il into wood or similar material while occupying relatively little space within the casing, so that the latter may be made relatively small and cornpact. Moreover, the mechanism is constructed so as to reduce the shocks and strains imposed on the hammer, thus materially increasing the useful life of that element.

In its preferred form, the actuating mechanism I9 comprises an elongated plunger 2| disposed within the upper casing compartment If'l and supported and guided for movement longitudinally thereof transversely of the reciprocatory path of the hammer I8. The plunger is supported and guided adjacent its rear end by a heavy cross member 22 rigidly secured to the side walls of the casing, the member being apertured to slidably receive the rear end portion ci the plunger which is preferably cylindrical and of reduced diameter as compared with the forward end portion thereof. The plunger is urged forwardly by suitable spring means, herein shown as a coiled compression spring 23 encircling the cylindrical end ,of the plunger and bearing at opposite ends against the cross member 22 and a rearwardly facing shoulder 24 formed on the plunger. Forward movement of the plunger is limited by an abutment member or head 25 engaging with the cross member 22. As herein shown, the head 25 comprises a nut threaded on the end of the plunger. A resiiient member or bumper 2B may be interposedI between the head and. the crossA member to absorb the shock incident to the interruption of the forward movement of the: plunger.

At its forward end the plunger 2'IJ is opera-- tively connected with the hammer t3 by atoggle: linkage which acts to transfer` the power of spring 23 to the hammer with a highr degreeof' elli.-A ciency and with a substantially complete absence of shock. As herein shown, the hammer I'8'comprises an elongated relatively thin stapleeengagfing tongue 3B secured to the front face of and projecting downwardly from` a vertically slottedl u guiding head. 3l.. 'IJhe toggle linkage comprises.. upper and lower links 32` and 33 connected by a pivot pin 34. The upper link is. pivotally se.- cured: to` the casing structure by a bolt 35 which. additionally serves as a pivot for the hand' lever 20. The link 33 extends into the slot in the harn-y mer head 3l and is pivotal-ly connected thereto byv apin. 36. Anarm 3.? rigid with. the link 33; and projecting rearwardly from the upper end thereof is: received in al slot. in the forward end of the plunger 2I andv is secured thereto by pivot pin 38.

Inthe. normal or idle condition of the machine the hammer I 8- is yield-ably urged to the advanced position shown in- Fig. 1,.- in whichy the: tongue 30. oftheI hammer is projected substantially flush withthe lower surface of the casing tu. As: the plunger is retracted, the spring. 23 is compressed and the hammer is shifted upwardly to, withdraw the tongue above the staple guideway .Y

I6 to permit the feeding of a staple into position to be driven by the downwardmovement of the tongue'. The compress-ion of the spring 23 thus prepares the hammer for delivery of a driving blow which is initiated by release ofthe plunger to the action of. the spring.

Means are provided for retracting the hammer I8 and for releasing it to the action of the compressed spring 23 by simply rocking the hand lever 29 down against the casing I0. The hand v lever, herein shown as a generally channel shaped sheet metal stamping adapted to fit over the casing, is pivotally supported at the front end of the casing, in this instance by the pin.

extending through the upper toggle link 32. The

rear portion of the lever extends over the top of the casing so that it may be readily grasped in the palm of the hand with the lingers gripping the casing through the opening II. Thus, a simple squeezing action provides the force required to compress the spring 23 and to retract the hammer I8.

To provide an operative connection between the. hand lever 2Q and plunger 2|, the lever carries a dog or pawl 40 adapted when the lever is depressed to engage an upright forwardly facing shoulder 4I on the plunger 2l to shift the plunger rearwardly. The cooperating parts of the pawl and. plunger are shaped so that the pawl is automatically disengaged from the shoulder II when the plunger reaches its fully retracted position. Upon such release the plunger is advanced by the spring 23 to drive the hammer downwardly, as above explained. K

In the exemplary machine the pawl 4f) comprises a generally rectangular member of steel or other suitable material, pivotally supported between the side flange of the lever 20 by a pin 52, the latter being located so that the pivotal axis of the pawl is disposed forwardly of the shoulder. One corner of the member is cut away or roundect off, as indica-ted; atI 43, to provide clearance so) thatthe pawl' may rockv between the position shown in Figs. 1 and 2, a torsion spring 44 yieldably urges the pawl to the upright position shown in Fig. 1, whereby its lower corner portion is positioned for operative engagement with. the: shoulder 4d. of the plunger.

To provide for. automatic disengagement of the pawl -frorm the' shoulder 4I, the plunger is formed with a cam surface 45 sloping upwardly from the base` of the' shoulder. The arrangement is suchf that as the plunger approaches its limit position the cam surface engages the forward edge of. the. pawl.. as shown in Fig. 3, and rocks the lever upwardly out of engagement with the shoulder... The. shoulder engaging portion of the pawl may be rounded or otherwise appropriately shaped, as indicated at.46,.to facilitate the. release of the plunger.

lever 20. from its. normali rest. position showni'n Fig. 1v to av position closely overlying. thetop. of the casing, as shown. in 2,. such. mow/tement serving to compress the spring 234 and thereby store up energy for advancing the hammer I8. i'n itsstaple driving stroke. and. to release the spring. and initiate the driving action.I The hammer. [K of course isretractedinthe. downward movement of the hand lever to permit the feeding, of astaple; into position to be driven. by the. hammer.

The novelI construction and relationship. of. the.

hammer I8' and its. driving mechanism, and par.- ticularly the mounting of the spring actuated plunger 2| for movement transversely of the. parir of the hammer, produces. a very compact. and conveniently shaped instru-ment.. Moreover.. novel arrangement of parts permits the casing III' to bev constructed of simple and. inexpensive parts conveniently produced by die, forming or stamping operations. In the exemplary embodiment, the casing I0 comprises a pair: of generally rectangular side plates and 5I having. inturned flanges 52 (Fig. 5)v at one edge. coacting to form the: fron-t wal-l ofthe casing.v Inturnedy flanges 54 and 55 (Fig. 6.) formed on the rear and top edges of the side plates and flangesY 56 encircling. the hand openings IzI inthe plates cooperate with the flanges 52 tohold the side plates in proper spaced relation when assembled. The flanges 56 additionally provide a smooth surface for gripping in the hand. The bottom of the casing I0, in. this instance, is formed by an elongated member or bottom stripy 60 adapted to fit between the side' plates 5I!` and 5I and having at its rear end a pair of laterally spaced upstanding. ears 6I. The ears BI are spaced apart so asy to straddle the side plates 5i) and 5I and assist inholding them in assembled relation'.

At its forward end the bottom strip 8.8. is provided with a. pair of laterally spaced bentfup lugs 62 adapted to t within a rearwardly lacing generally U-shaped member 63 which serves as a front plate for the lower portion of the casingA The latter is cut away 0r notched to-receive the front member and the lugs I2,.which are positioned tolie substantially flush with the side plates. The legs of the front member extend rearwardly and are spaced apart so as to straddle Accordingly.. the. driving, of. ay staple m-ay be effected. by merelyrockingtlle liarld the side plates lilly and 5l and assist furtherpin holding the plates in assembled relation. A suitable bolt or screw 64 (Figs. 1, 2 and 5) extends through the legs of the front plate and through the side plates for securing the parts together. The front member 63 and bottom member Se are formed with cooperating means for holding the latter in place. As herein shown, the cooperating means comprises tabs 65 (Fig. 6) projecting forwardly from the lugs 62 and engaging in notches 66 in the front member. At the rear end of the casing the parts are secured together by a pin 61.

The staple guide I6 previously referred to includes a channel-shaped member 68 secured to the bottom plate 60 in upwardly faced relation and extending longitudinally of the same. The member 68 preferably terminates a short distance rearwardly of the front member 63 to provide an opening for the passage of staples and the staple driving tongue 3l) of the hammer. Guide strips 69 rigidly secured to the side plates 50 and 5I extend generally parallel to the guide member 68 and project inwardly to overlie the ends of the staples carried on the member to maintain the staples on the guide in all positions of the machine. As shown in Figs. 1 and 2, the guide strips are notched similar to the side plates 50 and 5| and the staple retaining function is performed by auxiliary guide elements 10 carried by the upstanding lugs 62 of the bottom plate.

As will be seen by reference to Figs. 1 and 2 of the drawings, the strips 69 are extended upwardly at 1| adjacent to the front end of the casing to serve as guides for the reciprocatory hammer head 3|. The front edges of the extensions 'll are spaced rearwardly from the flanges 52 of the side plates and thus form guide channels 12 for slidably receiving the marginal edge portions of the tongue 30, whereby the hammer i8 is guided for reciprocation.

The feeding mechanism for advancing the staples on the guides I6 may be of conventional type, and as herein shown, comprises a channelshaped shoe 13 adapted to straddle the channel member 68. The shoe is slidably mounted on an elongated rod 14 by means of spaced depending lugs 'I5 struck from the upper Wall of the shoe and apertured to receive the rod. A spring 16 interposed between a laterally projecting arm 11 at the rear end of the rod and shoe urges the latter forwardly, thus tending to push the staple l'l into position to be driven by the hammer I8. The feed mechanism is retained in place in the casing by the arm 11, which is formed with a hook-like end adapted to engage a pin 'i8 within the casing. The latter is open at its rear end so that the hook may be disengaged and the entire mechanism withdrawn for loading staples on the guide channel. A head 19 on the forward end of the rod M prevents the shoe from being pushed off when the mechanism is withdrawn from the casing.

It will be apparent from the foregoing that the invention provides a stapling machine of novel and advantageous construction. The driving mechanism is very simple and compact, yet powerful and efficient in operation. Shocks and strains imposed on the operating elements of the machine are reduced to a minimum, and the parts subject to wear are readily accessible for replacement. The machine is light in weight and conveniently fits the hands of the operator so that it may be used for long periods without causing undue fatigue.

I claim as my invention:

1. A staple driving machine having, in combination, a reciprocating staple driving hammer, feed mechanism for presenting a succession of staples to said hammer when the latter is retracted, means for reciprocating said hammer includingY a plunger supported for movement transversely of the path of the hammer, a linkage connecting said plunger with said hammer, spring means acting on said plunger and urging the plunger and said hammer to an advanced position, manually operable means for retracting the plunger and said hammer against the force of said spring means, and means operative automatically upon predetermined retraction of said plunger for releasing said manually operable means therefrom, said spring means acting upon such release to advance said hammer to drive the staple presented thereto.

2. In a staple driving machine, in combination, a casing, a reciprocable hammer supported and guided at one end of the casing, a plunger supported in the casing for movement transversely of said hammer, a toggle linkage connecting said plunger and said hammer, spring means acting on said plunger tending to advance said plunger, a hand lever pivoted on said casing, a pawl carried by saidhand lever engageable with said plunger upon actuation of the lever to retract the plunger and said hammer against the force exerted by said spring means, said plunger being shaped to disengage said pawl upon a predetermined retraction whereby to free the plunger and said hammer to the action of said spring means.

3. In a staple driving machine, in combination, a casing, a reciprocating hammer in said casing, means for reciprocating said hammer including a plunger slidably supported in said casing, a linkage connecting said plunger and said hammer, spring means urging said plunger and said hammer to an advanced position, a hand lever pivoted on said casing, a pawl pivotally secured to said lever and having its free end engageable against a shoulder formed on said plunger whereby to retract the plunger upon depression of said lever, said plunger having a cam surface disposed forwardly of said shoulder operative to raise the free yend of said pawl out of engagement with said shoulder upon further depression of said lever, said spring means acting upon such disengagement of the pawl to advance said plunger and said hammer.

4. A staple driving machine having, in combination, a hollow generally rectangular casing having an elongated opening extending through opposite sides and dividing the interior thereof into a front compartment opening into vertically spaced rearwardly extending upper and lower compartments, a reciprocating hammer mounted in the vfront compartment, staple feeding mechanism mounted in the lower compartment, a hammer actuating plunger mounted in the upper compartment, a hand lever pivoted on said casing adjacent the upper end of the front compartment and extending rearwardly along the top of the casing, and means providing an operative connection between said lever and said plunger, the portion of said casing defining said upper chamber serving a-s a hand grip for operating said lever.

5. In a staple driving machine, in combination, a reciprocating hammer, means for reciprocating said hammer-including a plunger slidabl-y supported for movement transversely of the path of said hammer, a linkage connecting said plunger with said hammer, spring means acting on said plunger to urge the hammer to an advanced position, a not-ch in said plunger presentn ing a gradual-lysloping -su-riace terminating in an abrupt forwardly facing shoulder, a l-ever supported to swing toward' and' from` said plunger, a pawl pivotally supported at one end on said lever,v the pivotal axis or said pa-Wll being located forwardly oi said notchl whereby the free end of the pawlis adaptedV to engage said shoulder and' retract said plunger in response to the depression of' saidl lever,- said pawl being rock-ed about its pivot in the depress-ion of said lever until the free end thereof is disengaged from said shoulder and the plunger thereby released to theaction of said spring means.

6. In a staplingmachine, in combination, a hollow sheet metal casing, a reciprocating hammer supported and guidedy at one end oi said casing, hammer reciprocating means including an elongated plunger having one end operatively connected by a toggle'mechanism with said hammer, a cross member in said casing apertured to slid-ably receive the other end of said plunger, a spring interposed between said cross member and a shoulder on said plunger yieldably urging the same in a direction to advance said hammer, and abutment 'means on said other end of the plunger engageable with said cross member to d'ene the lim-it position of the plunger and said hammer.

7. In a staple driving machine, in combination, a hammer supported and guided for reciprocation, hammer actuating 'mechanism including a plunger supported and! guided for reciprocation transversely of the reciprocatory path of the plunger, spring means yieldably urging said plunger towardan advanced position, means for retracting saidI plunger against the forceI exerted by said spring and for releasing the. plunger to the action of thespring, and means interposed between said plunger and said hammer operative to transmit the movements of the plunger to the hammer.

8. In a staple driving machine, in combination, a, hammer supported' and guided for reciprocation, hammer. actuating mechanism including a plunger supported and guided for reciprocation. transverselyv oi the reciprocatory path off the hammer, spring means yieldably urging said plunger toward an advanced position, means for retracting said' plunger against. the force exerted by; said spring and' for releasing the plunger to the action. of' the spring, and a toggle linkage. operative to transmit the movements of saidl plunger to said hammer.

9. In a stapling machine, in combination, a staple driving hammer, mechanism for actuating said hammer, feedv mechanismy for supplying a succession of staples; to said hammer, a casing enclosing said hammer andsaid mechanisms including a pair of complemental side mem-bers, a bottom memberadapted to nt between said side members, a pair of upstanding ears at one end of said bottom member adapted to straddle said side members adjacent the rear end of the casing for holding the members in assembled relation, and a generally U-shaped front member adapted to nt over the iront end ofthe-casing to holdv the side members in assembled relation.

10. In a stapl-ing machine having a staple driving hammer, hammer actuating mechanism and staple feeding mechanism, the combination of a casing for enclosing said' hammer and said mechanisms comprising a pair of' complemental side members assembled to face-to--face relation, a iront member secured to said side members and adaptedto hold them in assembled relation, a bottom member having means forming a guide- WayA for staples. to be acted on by said feeding mechanism, and' means securing said' bottom member tosaid casing for convenient'y detachment to. permit removal of' jammed staples, said securing means including elements at one end of' said bottom member coacting withsaid'front member, and other elements adjacent the op posite end of said bottom member adapted to extend over-said side members and to be secured thereto.

11. In a stapl-ingv machine having a staple driving hammer, hammer actuating mechanism and staple feeding;- mechanism, the combination of a casi-ng for enclosing said hammer and' said mechanism comprising; aA pair' of complemental side members assembled in face-toface relation, a frontV member secured to saidI side members and adapted to hol-d them assembled rela-- tion, abottom member having means forming a guideway for staples tol be acted on by said feeding mechanism, and means securingl said bottom member to said casing for convenient detachment-to permit. removal of jammed staples, saidsecuring means including tabs projecting from the front end of said bottom member and engaging in notches in said fron-t mem-ber, and upstanding ears. adjacentv the rear end of said bottom. member extending over and secured. to said side members.

MELVILLE EARL WAMIELER..

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date- 1,.457,4'46 Michener June 5.,. 1923 1,709,756 Szepe Apr. 16., 192,9 161,449 Blumenbaum June 6, 1939 21S-114,847 Pelzer Mar. 23', 1943 2,341,530 Crosby Feb. 15,v 1944 2,346,834 Wheeler Apr. 13, 1944 

